The present invention relates generally to toys for use in water, and more particularly to hydrodynamic toys that can be hand-launched to travel along selected underwater trajectories.
Aerodynamic toys capable of being hand-launched through the air have been known for many years, and include balls, flying discs, boomerangs, toy gliders, etc. Aerodynamic toys typically are characterized by a combination of properties allowing a user to launch the toy into the air by hand so that the toy travels a substantial distance through the air along a trajectory selected by the user. Specifically, each of these toys has a size and shape that, in relation to the weight of the toy, enables an average user to apply a launching momentum sufficient to overcome, at least temporarily, the forces of gravity and wind-drag on the toy. Some aerodynamic toys are also configured to create lift when launched through the air to increase the distance the toys travel before descending to the ground.
While hand-launchable, aerodynamic toys are well-suited for use in air, they are not well-suited for use underwater, because water is a different medium than air. For example, objects traveling through water experience a significantly higher amount of drag than do objects traveling through air, because water has a much higher density than air. Similarly, objects experience a greater buoyancy in water than in air due to the higher specific gravity of water than air. For these reasons, toys intended for use underwater should employ hydrodynamic rather than aerodynamic values and thus typically will have different combinations of size, shape, and weight, than those intended for use m air.
In my existing U.S. Pat. No. 5,514,023, the disclosure of which is hereby incorporated by reference, I disclosed a hand-launchable projectile toy that was hydrodynamically configured to travel substantial distances underwater. In addition to having an elongate, smoothly-contoured body, the toy included a plurality of stabilizing fins projecting radially from the tail section of the body. This toy is currently available from SwimWays Corp., of Virginia Beach, Va., under the trademark TOYPEDO(copyright). Another example of a hand-launchable underwater projectile toy with radially projecting fins is the xe2x80x9cPoolarisxe2x80x9d toy distributed by Tony U.S.A., Inc., of Encinitas, Calif. At least one version of the xe2x80x9cPoolarisxe2x80x9d toy includes five radially projecting fins which are slightly inclined relative to the long axis of the projectile.
As disclosed in my prior patent, one embodiment of my earlier hydrodynamic projectile toy includes an elongate body with a generally cylindrical mid-section, and with generally rounded-conical nose and tail sections. The body of the projectile is sized to be comfortably gripped in a user""s hand. The projectile is substantially neutrally-buoyant in most bodies of water, having a specific gravity of between approximately 0.90 and approximately 1.1. A fillable internal cavity enables a user to adjust the buoyancy by adding water to the cavity. The shape and surface preparation of the projectile body provide a drag coefficient of less than approximately 0.15. The combination of relatively high mass, adjustable buoyancy, and low hydrodynamic drag allow the projectile to be hand-launched to travel at high speed over large distances underwater. The radially projecting fins function to stabilize the projectile during underwater travel by providing righting-moments in the event the projectile undergoes yaw or pitch.
While my earlier hand-launchable, underwater projectile toy enables a wide range of aquatic recreation activities, additional games, contests, and other play and/or skill activities would be possible with hand-launchable, underwater projectile toys of different configurations.
The invention provides a hand-launchable underwater projectile toy which gives a user increased options for aquatic games, contests, and other activities. In one embodiment, the toy includes a hydrodynamic body having a nose section, a tail section, and a mid-section extending therebetween. The mid-section is sized for grasping by a user""s hand, such as in the notch formed by the user""s thumb and index finger. A novel trajectory stabilizing structure extends from the body and is configured to impart a righting-moment to the body during underwater travel. The stabilizing structure includes one or more drag-producing surfaces extending in a non-radial direction with respect to the central axis. In another embodiment, the toy includes a stabilizing structure with at least one portion that is user-adjustable to impart a selected steering-moment to the body during underwater travel.
In a further embodiment, the invention provides a self-orienting, hand-launchable underwater projectile toy. The body of the projectile includes a positively buoyant first portion, and a negatively buoyant second portion. When the toy is suspended in water, the first and second portions cooperate to urge the body into a selected orientation.